Studies On Tissue Residues Depletion Of Sarafloxacin And Its Major Metabolites In Swine

Sarafloxacin(Sar),a fluoroquinolones,is widely used in China as an antibacterial agent in veterinary clinic.It is effective,with a broad antibacterial spectrum,to treatment susceptible bacterial or mycoplasma infection of livestock and poultry.The sarafloxacin injection is allowed to be used for the treatment of bacterial infection of pigs in China.However,international organizations and countries around the world had not set the the maximum residue limit of sarafloxacin in pig tissues.Therefore,it’s urgent to set the the maximum residue limit of sarafloxacin in pig tissues(muscle,liver,kidney,fat),so as to lay the foundation for the withdrawal period of the related drugs and the residual monitoring.46 healthy adult pigs were randomly divided into blank group and experiental group,the latter were randomly divided into nine groups and administrated intramuscularly with Sarafloxacin,at a dosage of 5 mg·kg-1 for consecutive five days.Five pigs were butchered at 4 h、12 h、24 h、48 h、72 h、120 h、168 h、240 h、360 h after the last dose,and samples of muscles,liver,kidney and fat were collected.The concentration-time data of sarafloxacin and its major metabolites were analyzed by Win No n Lin 6.1 sofeware.The results showed that the sarafloxacin quickly generated metabolites and the concentration of sarafloxacin was higher than other main metabolites in all edible tissues.Under this method,the result showed a good linear relationship between the peak area and the concentration of Sarafloxacin and its major metabolites during their linear ranges with correlation coefficient more than 0.99.At high,medium and low fortified levels,the recovery rates of sarafloxacin and its major metabolites in various tissues were between 70.0%~96.6%.The intra-assay coefficients of variation were between 0.61%~3.63%,while inter-assay coefficients of variation between 1.20%~4.75%,consistent with the requirements of residue analysis.The limit of detection(LO D)and the limit of quantification(LOQ)of sarafloxacin and its major metabolites in pig tissues mostly distributed among 0.2-1.0 μg/kg,except that some were 10.0-40.0 μg/kg.In this experiment,the residual elimination experiment of sarafloxacin in the pig was carried out,and a multi-residue detection method was developedted to determined salafloxacin and its main metabolites simultaneously.Salafloxacin with the largest area under the curve(AUC)of 208203.4 h·ng·g-1 in the kidney had the longest elimination half-life(t1/2β)of 82.11 h in the muscle.M1 had the largest area under the curve and the longest half-life in the liver,the parameters were as follows: AUC 7281.60 h·ng·g-1,t1/2β 104.05 h.The largest area under the curve in the kidney of 22008.0 h·ng·g-1and the longest half-life in the liver of 99.19 h occurred to M2.The parameters of M3 for the largest area under the curve in the kidney and the maximum elimination half-life in the liver were 29289.8 h·ng·g-1 and 115.00 h.M4 in the kidney had the largest area under the curve of 269.80 h·ng·g-1,while the elimination of the longest half-life in fat was 77.00 h.The results showed that sarafloxacin was the marker residue in the pig.Bceause the residual concentration in the kidney was higher and the residual time was longer,so the target tissue of sarafloxacin in pig tissue was kidney.The withdrawal time of sarafloxacin in pigs was 13 days.Meanwhile,the MRLs of Sarafloxacin was recommended to be 61.0 ng/g in muscle,340.4 ng/g in fat,134.3 ng/g in liver,275.9 ng/g in kidney.